Was it a formal PIP, though? In my experience there are many managers who'll do that for employees that they wish to retain, but who, for various reasons, aren't performing up to snuff. However, I've never heard of a manager bringing HR in, doing the PIP paperwork, and the employee surviving the PIP. In general, the moment HR gets involved (either in person or via formal paperwork) between you or your manager, you know you're done. As others have stated, treat the time of your PIP as a form of severance pay, do the minimum amount of work necessary to not get fired that day, and look for a job elsewhere.